• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.413-422
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• 1997

Fire characteristics of a typical apartment building in Korea was studied through full scale experiment and zone model simulation. The fire was ignited at the living room and allowed to spread to other parts of a single unit in a five storied apartment building. Various data including temperatures, species concentrations, and images were collected in the experiment. A zone model(CFAST) was used to analyze the same apartment building that represents the average households in Korea. The results were compared with a full scale experiments. While CFAST allows one compartment involved with fire, the experiment allowed the fire to spread to other compartments. Therefore, the comparison between experimental data and Zone-Model data is valid until the living-room fire spread to other parts of the apartment. Flashover occurred at approximately 380 seconds in a fire experiment, and at approximately 420 seconds in Zone-Model. Based on all of data between experimental data and Zone-Model data, it is concluded that the safe escape time is about 250 seconds.

• 대한토목학회논문집
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• 제39권6호
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• pp.833-839
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• 2019

BIS (Bus Information System:버스정보시스템, 이하 BIS)는 시내버스 운행과 관련된 각종 정보를 수집하고 예측알고리즘을 통해 이용객에게 정보를 제공하고 있다. 동일 구간의 최근 정보를 통한 예측방법은 해당 구간의 소통상황을 반영하지만 예측 대상노선의 특성을 반영할 수 없다는 한계가 있다. 해당노선의 동시간대 과거이력자료를 통해 예측하는 방법은 소통상황의 변동성이 큰 첨두시 예측에 한계가 있는 실정이다. 따라서 예측대상 시점의 통행패턴을 인식하고 가장 유사한 과거 시점의 통행패턴을 선택할 수 있는 패턴인식형 버스도착시간 예측 알고리즘을 개발하였다. 본연구의 예측 결과를 서울시 BIS 도착예측정보이력과 비교 검증한 결과 각 정류장 간 통행시간의 평균제곱근오차가 비첨두시 약 35초(기존: 40초), 첨두시 약 40초(기존: 60초)로 기존대비 약 10~20 %의 개선을 보였다. 이는 동일 과거 시간대 외의 시간대에 현재 교통상황을 대표할 수 있는 자료가 존재함을 의미한다.

• Journal of Welding and Joining
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• 제16권5호
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• pp.108-118
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• 1998

This study proposes th analysis and evaluation method of time series ultrasonic signal using the chaos feature extraction for ultrasonic pattern recognition. Features extracted from time series data using the chaos time series signal analyze quantitatively weld defects. For this purpose, analysis objective in this study is fractal dimension and Lyapunov exponent. Trajectory changes in the strange attractor indicated that even same type of defects carried substantial difference in chaosity resulting from distance shifts such as 0.5 and 1.0 skip distance. Such differences in chaosity enables the evaluation of unique features of defects in the weld zone. In quantitative chaos feature extraction, feature values of 4.511 and 0.091 in the case of side hole and 4.539 and 0.115 in the case of vertical hole were proposed on the basis of fractal dimension and Lyapunov exponent. Proposed chaos feature extraction in this study can enhances ultrasonic pattern recognition results from defect signals of weld zone such as side hole and vertical hole.

• 대한기계학회논문집A
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• 제23권7호
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• pp.1065-1074
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• 1999

This study proposes the analysis and evaluation method of time series ultrasonic signal using the chaotic feature extraction for ultrasonic pattern recognition. Features extracted from time series data using the chaotic time series signal analysis quantitatively welding defects. For this purpose analysis objective in this study is fractal dimension and Lyapunov exponent. Trajectory changes in the strange attractor indicated that even same type of defects carried substantial difference in chaoticity resulting from distance shills such as 0.5 and 1.0 skip distance. Such differences in chaoticity enables the evaluation of unique features of defects in the weld zone. In experiment fractal(correlation) dimension and Lyapunov exponent extracted from 6dB ultrasonic defect signals of weld zone showed chaoticity. In quantitative chaotic feature extraction, feature values(mean values) of 4.2690 and 0.0907 in the case of porosity and 4.2432 and 0.0888 in the case of incomplete penetration were proposed on the basis of fractal dimension and Lyapunov exponent. Proposed chaotic feature extraction in this study enhances ultrasonic pattern recognition results from defect signals of weld zone such as vertical hole.

• 한국정밀공학회지
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• 제15권11호
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• pp.152-165
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• 1998

This study proposes the analysis and evaluation method of time series ultrasonic signal using the chaoral post-process system for precision rate enhancement of ultrasonic pattern recognition. Chaos features extracted from time series data for analysis quantitatively weld defects For this purpose, feature extraction objectives in this study are fractal dimension, Lyapunov exponent, shape of strange attrator. Trajectory changes in the strange attractor indicated that even same type of defects carried substantial difference in chaoticity resulting from distance shifts such as nearby 0.5, 1.0 skip distance. Such difference in chaoticity enables the evaluation of unique features of defects in the weld zone. In quantitative chaos fenture extraction, feature values of 0.835 and 0.823 in the case of slag inclusion and 0.609 and 0.573 in the case of crack were suggested on the basis of fractal dimension and Lyapunov exponent. Proposed chaoral post-process system in this study can enhances precision rate of ultrasonic pattern recognition results from defect signals of weld zone, such as slag inclusion and crack.

• 한국물환경학회지
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• 제34권5호
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• pp.462-469
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• 2018

There are differences in method and cycle of flow rate survey depending on purpose of the operating department. To verify and use results of flow data according to the purpose, flow data of the directly measured and tele monitoring system were compared to verify validity. Flow measurement in the Ministry of Environment is aimed at setting up a standard flow of target water quality for water quality management and securing flow data of low and normal water level seasons for water quality evaluation. In this study, correlation analysis result ($R^2$) of same time zone data by direct measurement and tele monitoring system (TMS) at Seombon D point, a unit watershed of Seomjin river, for six years ('10 ~ '15) according to implementation of Total Daily Maximum Load (TDML) was wading 0.716, boating 0.962 and on bridge 0.943, and effectiveness of measurement method was verified by characteristics of flow duration as a season of dry and low-water; normal and high water are appropriate for wading, boating, and on bridge respectively. Results revealed it is reasonable to use directly measured results using the wading and boating method for low water level and dry seasons, and TMS data for rainy seasons. It can be used important data for future policy decisions.

• 대한기계학회논문집B
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• 제20권5호
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• pp.1671-1678
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• 1996

In external chemical vapor deposition processes including VAD and OVD the distribution of flame-synthesized silica particles is determined by heat and mass transfer limitations to particle formation. Combustion gas flow velocities are such that the particle diffusion time scale is longer than that of gas flow convection in the zone of particle formation. The consequence of these effects is that the particles formed tend to remain along straight smooth flow stream lines. Silica particles are formed due to oxidation and hydrolysis. In the hydrolysis, the particles are formed in diffuse bands and particle formation thus requires the diffusion of SiCl$\_$4/ toward CH$\_$4//O$\_$2/ combustion zone to react with H$\_$2/O diffusing away from these same zones on the torch face. The conversion kinetics of hydrolysis is fast compared to diffusion and the rate of conversion is thus diffusion-limited. In the language of combustion, the hydrolysis occurs as a Burke-Schumann process. In selected conditions, reaction zone shape and temperature distributions predicted by the Burke-Schumann analysis are introduced and compared with experimental data available. The calculated centerline temperatures inside the reaction zone agree well with the data, but the calculated values outside the reaction zone are a little higher than the data since the analysis does not consider diffusion in the axial direction and mixing of the combustion products with ambient air. The temperatures along the radial direction agree with the data near the centerline, but gradually diverge from the data as the distance is away from the centerline. This is caused by the convection in the radial direction, which is not considered in the analysis. Spatial distribution of silica particles are affected by convection and diffusion, resulting in a Gaussian form in the radial direction.

• 생태와환경
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• 제43권4호
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• pp.471-476
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• 2010

Monthly up-river discharge in the riverine zone analysis resulted in large interannual variations and differences in calcium ($Ca^{2+}$), bicarbonate ($HCO_3^-$), and cations in the lacustrine zone (Lz) of Daecheong Reservoir during the wet year (Wy, 1993) vs. dry year (Dy, 1994). Total up-river discharge in the Wy was four times that of the Dy, and the up-river discharge in July~August of the Wy was eight times greater than that of same period of Dy. Annual water retention time in the Lz showed large difference between the two years. Water residence time (WRT) was minimum when the up-river discharge peaked, whereas the WRT was maximum when the up-river discharge was at minimal condition. This peak discharge from the up-river on early July reduced residence time in the Lz on mid-July~late July. Monthly pattern, based on data of May~November, was similar between the two years, but, but mean retention time in the Wy was 50 days shorter than in the Dy. Such hydrology, up-river discharge, and WRT reduced $Ca^{2+}$, $HCO_3^-$, and cations in the Lz. At low up-river discharge in Wy during April~May, the cation content of Ca+Mg+Na+K averaged 1.17meq $L^{-1}$ (range=1.09-1.26meq $L^{-1}$), but as the up-river discharge increased suddenly, the values decreased. Seasonal fluctuations of $Ca^{2+}$ showed exactly same pattern with bicarbonate ion of $HCO_3^-$. The minimum $Ca^{2+}$ (0.03meq $L^{-1}$) was occurred in the early August of wet year and coincided with the minimum $HCO_3^-$. These results suggest that the magnitude of variation in $Ca^{2+}$, bicarbonate, and cations in the lacustrine zone is directly determined by the peak magnitude of up-river discharge. The magnitude of up-river discharge determined water retention time and the magnitude of ionic dilution in the lacustrine zone, resulting in functional changes of the ecosystem.

• 한국실내디자인학회논문집
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• 제24권2호
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• pp.125-133
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• 2015

Gaze induction characteristics in space vary depending on characteristics of spatial components and display. This study analyzed dominant eye-fixation characteristics of three zones of department store space. Eye-fixation characteristics depending on spatial components and positional relationship can be defined as follows. First, [**.jpg] was used as an extension in the process of storing the image photographed during image data processing for analysis in pixels and due to compressed storage of image data, the image produced with a clear boundary was stored in neutral colors. To remove this problem, the image used in operation was re-processed in black and white and stored in the [**.bmp] format with large capability, at the same time. As the result, the effort caused by unnecessary colors in the program operation process was corrected. Second, the gaze ratio to space area can be indicated as a strength of each gaze zone and when analyzing the gaze strength of the three zones, the left store was a zone with a "little strong" gaze strength of "102.8", the middle space was a zone with an "extremely weak" gaze strength of "89.6" and the right store was a zone with an "extremely strong" gaze strength of "117.2". Third, the IV section had a strong strength of gaze on the middle space and the right store and the V section showed a markedly strong strength of gaze on the left and right stores. This tendency was the same as the VI section with the strongest gaze strength and the right store had a little strong gaze strength than the left store.

• 한국해안·해양공학회논문집
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• 제27권3호
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• pp.190-196
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• 2015

육상의 바람정보를 이용하여 해상 바람을 추정하는 방법은 매우 빈번하게 사용되어 왔다. 그러나 자료의 특성에 근거하여 그 방법의 한계를 검토하는 연구는 매우 미흡하다. 본 연구에서는 육상자료를 이용한 해상자료 추정의 정량적인 한계를 검토하기 위하여 포항 연안의 육상과 바다에서 관측한 바람자료의 특성을 비교 분석하였다. 특히 기존에 간과되던 방향 자료 분석에 중점을 두고 연속적인 풍향 자료 분석 기법을 제안하였다. 분석 결과, 연안해상의 바람자료는 육상과 매우 인접한 지점에 위치하고 있음에도 불구하고 바람정보의 통계적인 분포 특성이 크게 차이가 나는 것으로 파악되었다. 따라서 육상정보를 이용한 해상 바람정보 추정은 지형적인 영향으로 특성 차이가 커서 근본적인 한계가 있기 때문에 관측 자료를 이용한 정량적인 오차 한계가 반드시 검토되어야 한다.